Plant Petiole Sap-Testing for Vegetable Crops
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How to Cite

Hochmuth, George, and Robert Hochmuth. 2022. “Plant Petiole Sap-Testing for Vegetable Crops: CV004/CIR1144, Rev. 5/2022”. EDIS 2022 (3). Gainesville, FL.


Various nitrate and potassium "quick-test" kits for vegetable plant sap-testing have been calibrated for use on Florida vegetables. The objective has been to find a system that growers can use in the field to help manage nitrogen (N) and potassium (K) fertilizer—especially for drip-irrigated vegetables. The following guidelines should help individuals who are currently using—or are interested in using—sap-testing. Revision by George and Robert Hochmuth published by the UF/IFAS Horticultural Sciences Department; 6 pages.
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Coltman, R. R. 1987. “Sampling Considerations for Nitrate Quick Tests of Greenhouse-Grown Tomatoes.” J. Amer. Soc. Hort. Sci. 112:922–927.

Fletcher, J., R. Hochmuth, and G. Hochmuth. 1993. “Calibration of N and K Fresh Sap Quick-Test Procedures for Polyethylene-Mulched Peppers.” Proc. 24th Natl. Agricultural Plastics Congr. 24:147–152.

Hochmuth, G., B. Hochmuth, E. Hanlon, and M. Donley. 1991. “Nitrogen Requirements of Mulched Eggplant in Northern Florida.” Suwannee Valley AREC Res. Report 91-14.

Hochmuth, G., D. Maynard, C. Vavrina, and E. Hanlon. 1991. “Plant Tissue Analysis and Interpretation for Vegetable Crops in Florida.” Fla. Coop. Ext. Serv. Special Series SS-VEC-42.

Hochmuth, G. J., P. R. Gilreath, E. A. Hanlon, G. A. Clark, D. N. Maynard, C. D. Stanley, and D. Z Haman. 1988. “Evaluating Plant N Status with Plant Sap Quick-Test Kits. Proceedings of Tomato Institute.” Fla. Coop. Ext. Serv. Spec. Series SS-VEC-801:6–14.

Hochmuth, G. J., B. C. Hochmuth, E. A. Hanlon, and M. E. Donley. 1992. “Effect of Potassium on Yield and Leaf-N and K Concentrations of Eggplant.” Suwannee Valley AREC Res. Report 92-2.

Hochmuth, R., S. Rider, D. Fenneman, E. Toro, and N. Parkell. 2015. “On-Farm and Small Plot Research Trials Comparing Petiole Sap Nitrogen and Potassium Concentrations for Seeded vs. Seedless Watermelon Cultivars.” UF/IFAS NFREC-Suwannee Valley Research Report.

Hochmuth, R. C., and G. J. Hochmuth. 1991. “Nitrogen Requirements for Mulched Slicing Cucumbers.” Suwannee Valley AREC Res. Report 91-18.

Prasad, M., and T. M. Spiers. 1984. “Evaluation of a Rapid Method for Plant Sap Nitrate Analysis.” Commun. Soil Sci. Plant Anal. 15 (6): 673–679.

Vann, C. D., R. C. Hochmuth, and G. J. Hochmuth. 1993. “Watermelon N and K Petiole Sap Testing.” Proc. 1993 Watermelon Institute. Fla. Coop. Ext. Serv. Special Series SS-HOS-003.

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